Alloy



Patented Oct. 26,1937

UNITED STATES PATENT OFFICE No Drawing. Application August 20, 1936,

Serial No. 96,997 i 3 Claims. (01. 148-321) The present inventionrelates to a new and useful alloy and relates particularly to an alloycontainingboron, tungsten and nickel, which is characterized by beingresponsive to thermal 5 treatment for the improvement of physicalproperties. M An object of the present invention is to provide an alloyespecially adapted for use as metal cutting tools, the cuttingefliciency of which is 10 superior to that of present known high speedsteels and other alloys. A further object is to provide an alloy whichis free from, or substantially free from carbon and which is readilyamenable to thermal treatment, by means of which the hardness, tensilestrength, cutting efliciency and other physical properties andcharacteristics may be accurately controlled over a comparatively widerange.

I have found through experiment that by al- 2 loying or otherwiseintimately combining boron, tungsten and nickel within the range ofboron 0.50% to 2.75%, tungsten 5% to and nickel .substantially thebalance, that I obtain metallic compositions which possess incombination me.-

5 terially improved physicalproperties compared to those of heretoforeknown alloysor compositions intended for the cutting orworking ofmetals. p I

'Alloys of this invention may be used in the 3 cast condition butapproximate. maximum values of hardness, resistance to impact and,certain other important physical properties. can be developed onlythrough thermal treatment, or

- through mechanical working and subsequent thermal treatment. Bodies ofthe alloys which have been subjected to such treatment are particularlyvaluable for use as tools, dies and the likefor the cutting ormechanical working of metals.-

Numerous-metallic compositions have heretofore been proposed asimprovement on the generally known 18-4-1 type oftungsten-chromium-vanadium high speed tool steel, and while many of suchcompositions possess: greater hardness than such steel, all of them havedisadvantages which render them unsuitable for general application asmetal cutting or forming tools.

' 1 Compositions containing principally carbides of tungsten, molybdenumor tantalum .bonded with a relatively soft matrix metal have a highdegree of hardness, but are extremely brittle. Cast compodtions of thetypes heretofore proposed require the presence of at least 1.50% carbonto qualify as metal cutting tools and, as is'well. known, such alloysare-not only brittle, but, are so sensitive to variousoperatingconditions as to greatly restrict the scope of usefulness. Oneof the greatest disadvantages of such heretofore proposed compositionsis that none of them are responsive to thermal treatment for regulationof physical properties, and 5 consequently physical properties-'andcharacter- 'istics are governed entirely by the chemical composition ofthe sintered or cast material.

My alloy may be usedin the as-cast condition, or it may be forged orotherwise mechanically l0 worked. I have found that both the cast andforged material are amenable to thermal treatment. For example, castbodies of this alloy may have a hardness of from 50 to on the RockwellC. scale and .by subjecting the .mate- 15 rial to suitable thermaltreatment, such as quenching from a temperature higher thanapproximately 1000 C., the hardness may be. owered to an approximaterange of from 40 to 4'7 Rockwell C. In this condition the bodies may 20be ground, shaped or formed, asdesired. The alloy may subsequently besubmitted to a second thermal treatment, such as heating to a temperaturof less than 1000 C. for a period of one hour or more, by which thehardness may 25 be increased to from approximately 60 to Rockwell C. Inthe latter condition the alloy' is especially valuable for the cuttingor mechanical working of a large number of metals and alloys, as well asnumerous non-metallic materials. An 30 important property of the alloyis that virtually all of the maximum hardness;'developed by thermaltreatment, is retained when, the ,alloy is subjected to elevatedtemperatures, e. g. such as are generated in the tip of a tool cutting 5metal at high speed. Although the alloy has a high degree of hardnessand resistance abrasion by hot metal chips, especially after thermaltreatment, it is remarkably resistant to failure from sudden or repeatedshock. Therefore, 40

' tools 'made of the present alloy retain an eflicient cutting edge forlonger-periods than other tools.

The more important distinctive and valuable advantages are, apparently,due to the presence of appreciable amounts of boronin the compo-' 5sition, in conjunction with the other component elements within thepercentages specified herein.

I have found that molybdenum may be used to supplant all or a portion ofthe tungstenoi' the 50 present alloy. Likewise, uranium may be vused inplace of either timgsten or molybdenum.

Specific examples of compositions within the scope of the presentinvention which I have found -well adapted for metal cutting tools, dies55 and. the like are the following: boron 1.20%,

tungsten 14%, nickel balance; boron 2.10%, tung-- sten 19.50%, nickelbalance; boron 1.65%, molybdenum 13%, nickel balance; boron 1.70%,tungsten 5%, molybdenum nickel balance.

An objective of the present invention is to provide alloys having highhardness, high resistance to shock and impact, advantageous metalcutting properties, etc., which are free from or substantially free fromcarbon, and thus eliminate all of the serious disadvantages associatedwith carbon containing non-ferrous alloys or compositions intended formetal cutting tools. Although I prefer to have the alloys ofthis'invention entirely free from carbon, in many instances I have foundcarbon present in the nature of an impurity incidental to manufacture.It is important to restrict the amount of carbon so present to a maximumof about 0.15%, as I have found that the presence of higher percentagesof this element make the alloy extremely brittle and subject to failureduring cutting operations, and also inhibits the desired and necessaryreactions during thermal treatment. Furthermore, the presence ofappreciable amounts of carbon decreases the red hardness of the alloy,i. e. hardness at temperatures of approximately 550 C. and higher.

By reason of the fact that the elements forming the essential componentsof the alloy of the present invention invariably are contaminated withother elements when produced in commercial quantities, the alloys of myinvention usually contain insignificant amounts of one or more elementsin the nature of impurities incidental to manufacture. The amount ofsuch impurities should be restricted to percentages which are notefiective on the physical properties or characteristics of the alloy,nor on the physical reactions during thermal treatment. I have foundthat the amount of any one of such incidental impurities should berestricted to percentages not exceeding 1%, and in many instances tomaterially lower percentages. The presence of larger amounts of suchimpurities, particularly silicon and aluminum, materially decreases the"resistance of the alloy to failure under shock and impact during cuttingoperations, and, further, inhibits the desired physical reactions duringthermal treatsecond. a solid solution of two or more of the essentialcomponents which has a lower degree of hardness and functions as amatrix. In some instances the structure will contain a third constituentin the nature of an eutectoid. The ratio of the constituents and theratio of particle size in any particular body of the alloy may beaccurately controlled and fixed over a wide range by means of thermaltreatment, or mechanical working and subsequent thermal treatment.

By reason of the combined advantageous physicalproperties possessed bythe alloy of the present invention, tools and other articles composed ofthis alloy may be operated efilciently and economically under conditionswhich are impossible or uneconomical with tools or articles composed ofheretofore known alloys or metallic compositions. I

I By the term "the balance substantially nicke in the foregoing andinthe following claims. I intend that the alloy of the present inventioncomprises boron and metal of the group tungsten, molybdenum and uraniumwithin the percentage limits specified, with the remainder nickel exceptfor ineffective amounts of impurities which may be present incidental tomanufacture.

I claim:

1. An age hardened alloy containing boron 0.50% to 2.75%, metal from thegroup tungsten, molybdenum and uranium 5% to 25%, the balancesubstantially nickel.

2. An age hardened alloy containing boron 0.50% to 2.75%, tungsten 5% to25%, the balance substantially nickel.

3. An age hardened alloy containing boron 0.50% to 2.75%, molybdenum 5%to 25%, the

balance substantially nickel.

ANTHONY G. DE GOLYER.

